Health

Coffee stimulation of cholecystokinin release and gallbladder contraction in humans

Article Abstract:

Since coffee is such a popular beverage in Western society, any link between coffee consumption and medical problems is of great importance. Epidemiologic studies of the possible association between coffee and pancreatic cancer have yielded contradictory results. A mechanism has been found in rats by which coffee could promote the development of cancer; substances, such as coffee, that continuously stimulate the pancreas by releasing cholecystokinin (CCK) were found to promote pancreatic cancer. CCK is a hormone that has important stimulating effects on both pancreatic secretion and gallbladder contraction. It is also known that both regular and decaffeinated coffee stimulate pancreatic secretion in healthy people. This study investigated the influence of coffee drinking on CCK release and contraction of the gallbladder. The subjects were six healthy, young adults who were regular coffee drinkers (at least two cups of coffee a day for five years or more). The effects of both regular and decaffeinated coffee were measured and compared with the effects of a ''control'' beverage, which consisted of hot water with salt added to reach the same osmolality (particle concentration) as coffee. Blood CCK levels rose more after the regular and decaffeinated coffee than after the control beverage. Gallbladder contraction was greatest after regular coffee, lower after decaffeinated coffee, and still lower after the control drink. It was concluded that both types of coffee cause increases in blood CCK and gallbladder contraction. However, this does not appear to be a justification for reducing coffee consumption, because eating a normal meal would have the same effects; therefore, it is not likely that coffee consumption would increase the vulnerability of the pancreas to cancer. The findings did confirm, however, that patients with gallstones should avoid drinking both types of coffee. (Consumer Summary produced by Reliance Medical Information, Inc.)

Besides calories, vitamins, and minerals, breast milk supplies infants with hormones and small proteins called peptides, which are important for infant health. A number of peptides, including gastric inhibitory peptide (GIP), bombesin, and vasoactive intestinal peptide (VIP), are involved in regulating gastrointestinal (GI) function. The amount of these GI neuropeptides in human breast milk was determined. Levels of GIP in breast milk remained constant throughout the first six postpartum months, while amounts of other GI peptides decreased. Bombesin levels in milk were three times those found in blood, implying that maternal cells actively took up bombesin from the blood or synthesized it. In comparing blood levels of GI peptides in pregnant versus control women, it was found that in pregnant women the levels of GIP were lower and those of VIP were higher. The study shows that breast milk supplies infants with significant amounts of GI peptides, which may improve the intestinal function of newborns in the two to four weeks before they are able to make their own gastrointestinal peptides. The breast milk peptides may also promote the maturation and growth of the infant's intestinal system. (Consumer Summary produced by Reliance Medical Information, Inc.)